Absolute acceleration sensor for use within moving vehicles

ABSTRACT

A communication system for a vehicle comprises a receiver to receive a signal corresponding to a traveling speed of a lead vehicle, a response device that generates an alert to warn of a change in the traveling speed of the lead vehicle, and a control device coupled to the receiver and the response device, wherein the receiver sends a signal to the control device corresponding to the traveling speed of the lead vehicle and the control device operates the response device in a manner dependent on the traveling speed of the lead vehicle. In some embodiments, the signal comprises one or more of infrared, radio frequency, wireless, WiFi, and Bluetooth®. In some embodiments, the communication system further comprises a speed control system coupled to the control device, wherein the control device operates the speed control system in a manner dependent on the traveling speed of the lead vehicle.

RELATED APPLICATION

This patent application is a continuation-in-part of the U.S. patentapplication Ser. No. 12/464,601, filed May 12, 2009, and entitled“ABSOLUTE ACCELERATION SENSOR FOR USE WITHIN MOVING VEHICLES,” which ishereby incorporated by reference in its entirety, which is acontinuation-in-part of the U.S. patent application Ser. No. 12/434,577,filed May 1, 2009, and entitled “ABSOLUTE ACCELERATION SENSOR FOR USEWITHIN MOVING VEHICLES,” which is hereby incorporated by reference inits entirety, which is a continuation of the U.S. patent applicationSer. No. 11/585,401, filed Oct. 23, 2006 and entitled, “ABSOLUTEACCELERATION SENSOR FOR USE WITHIN MOVING VEHICLES,” now issued as U.S.Pat. No. 7,529,609, which is hereby incorporated by reference in itsentirety, and which is a continuation-in-part of U.S. patent applicationSer. No. 11/243,364, filed Oct. 3, 2005 and entitled, “ABSOLUTEACCELERATION SENSOR FOR USE WITHIN MOVING VEHICLES”, now issued as U.S.Pat. No. 7,239,953 B2, which is hereby incorporated by reference in itsentirety, and which claims priority under 35 U.S.C. 119(e) of the U.S.provisional patent application No. 60/616,400, filed on Oct. 5, 2004,and entitled “REAR-END COLLISION AVOIDANCE SYSTEM,” which is also herebyincorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to methods and devices fordetecting absolute levels of longitudinal, lateral and verticalacceleration within moving vehicles, and to a variety of systems andmethods for generating responses to changes in these absolute levels.

BACKGROUND OF THE INVENTION

Accelerometers find a wide variety of applications within modern motorvehicles. The most common of these are impact and collision sensors usedto deploy front and side impact air bags in modern passenger cars andtrucks.

In applications that depend on sudden and drastic deceleration, thepresence of gravity is of little consequence and will not affect theimplementation of the accelerometer. However, increasingly feedbacksystems within motor vehicles have attempted to make use ofaccelerometer data during much lower and subtler levels of acceleration.

One example is anti-collision warning systems. Though all street legalmotor vehicles have brake lamps configured to signal other drivers ofbraking, these signals do not warn following drivers of imminentbraking. At least one system has proposed activating a vehicle's brakelamp system in response to a deceleration signal from a sensitiveaccelerometer, and independent of actuation of the brake pedal. Thesystem described in U.S. Pat. No. 6,411,204 to Bloomfield et al.,entitled “DECELERATION BASED ANTI-COLLISION SAFETY LIGHT CONTROL FORVEHICLE,” includes a plurality of deceleration thresholds each with anassociated modulation of the brake lamps.

However, the system fails to precisely account for gravitational forces,limiting its effectiveness to deceleration regimes where gravity'seffect is minimal and reducing its effectiveness as an early warningsystem. Accelerometers, known as tilt sensors in the gaming and roboticsindustries, are extremely sensitive to any gravitational force to whichthey are not perpendicular. This sensitivity complicates any system thatattempts to detect low levels of acceleration by using accelerometerswithin moving vehicles, since the system must account for the widevariety of orientations of the accelerometer relative to the earth'sgravity introduced as the vehicle travels uphill, downhill, throughcambered or off-camber curves, and on cambered grades. For instance, anaccelerometer in a vehicle stopped on a 45-degree downhill slope wouldsense deceleration of a magnitude equal to 0.71 times the accelerationdue to gravity. To avoid gravitational acceleration artifacts, thesystem of Bloomfield only produces output if the deceleration signalrises above a predetermined threshold set above the level of artifactsintroduced during typical driving conditions.

However, the reliance of this device on a threshold deceleration reducesits effectiveness as an early warning system. Even a short delay betweenthe time when the subject vehicle begins to slow down and the time whena following vehicle begins to slow can result in a rapid closure of thegap, or following distance, between the vehicles, and a potentialcollision. Consequently, the shorter the following distance betweenvehicles, the smaller the margin of error will be for drivers offollowing vehicles to avoid rear-end collisions. Disengaging theaccelerator, or coasting, is often the first response of the driver of asubject vehicle to observing a non-urgent traffic event in the roadwayahead, and usually results in a slight deceleration. By failing to warnother drivers of the possible imminence of braking of a subject vehicle,the proposed device loses valuable time. To avoid this problem, thethreshold must be set lower, which could result in gravitationalacceleration artifacts affecting the system's output. For example, anoverly low threshold could prevent the device from signalingdeceleration on an uphill grade since the accelerometer would sense acomponent of the earth's gravity as acceleration. Similarly, a lowthreshold could cause the device to continuously flash during a descent,while gravity appears as deceleration.

The loss of time incurred by a threshold-based system might be tolerablein some other application; but in collision prevention, even an instantsaved can prevent a collision. A Special Investigative Report issued inJanuary of 2001 by the National Transportation Safety Board (NTSB)illustrates the scale of the problem. The report notes that in 1999“1.848 Million rear-end collisions on US roads kill[ed] thousands andinjur[ed] approximately [one] Million people.” The report concluded thateven a slightly earlier warning could prevent many rear-end collisions.

-   -   Regardless of the individual circumstances, the drivers in these        accidents were unable to detect slowed or stopped traffic and to        stop their vehicles in time to prevent a rear-end collision. If        passenger car drivers have a 0.5-second additional warning time,        about 60 percent of rear-end collisions can be prevented. An        extra second of warning time can prevent about 90 percent of        rear-end collisions. [NTSB Special Investigative Report        SIR-01/01, Vehicle- and Infrastructure-based Technology for the        Prevention of Rear-end Collisions]

In some instances, a motor vehicle will remain running while parked ornot in use, in an “idling” state. Common reasons for idling includewaiting for a passenger, warming up the vehicle, listening to the radioand convenience. Motor vehicles that remain in an idling state polluteour environment unnecessarily. For example, thirty seconds of idling canuse more fuel than turning off the engine and restarting it.Additionally, idling for ten minutes uses as much fuel as traveling fivemiles. Moreover, one hour of idling burns up to one gallon of fuel andcan produce up to 20 lbs of carbon dioxide, which contributes to globalwarming. Passenger cars, fleet vehicles, diesel trucks, busses andtaxi-cabs are all culprits in adding to pollution through unnecessaryengine idle.

At present, over 30 states and 900 municipalities have adopted lawsrestricting the amount of time a stationary vehicle is allowed to idlebefore being turned off. These laws typically limit the allowable idlingtime from 1 to 6 minutes before the engine must be turned off andviolations can range up to $1,000 per incident. Corporate and governmentfleet vehicles are most susceptible to such monetary penalties becausethe aggregate impact of many violations may reside within only oneentity.

SUMMARY OF THE INVENTION

In this application “acceleration” refers to either or both positiveacceleration and negative acceleration (sometimes called“deceleration”), while “deceleration” refers to only negativeacceleration.

The present invention provides systems and methods for warning driversof other vehicles of any possibility that a subject vehicle will brakeand/or that the following vehicle may need to decelerate. This warningoccurs earlier than warnings provided by traditional rear brake warningsystems. Some embodiments of the present invention take advantage of theexisting conditioning of modern drivers to respond quickly to rear brakewarning lamps by using these systems to convey new decelerationwarnings.

Some embodiments of the present invention relate to devices thatovercome the limitations of the prior art by integrating the signalsfrom pulse or sine wave generators, which are directly related tovehicle distance traveled per unit of time. These devices are commonlyreferred to as vehicle speed sensors (VSS). Most modern vehicles areshipped with an electronic VSS as standard equipment. The stock VSScommunicates with the vehicle's electronic control module (ECM) andspeedometer to display the speed of the vehicle to an operator. However,VSS can be installed as aftermarket add-ons.

The embodiments of the present invention involve using signals from avehicle's VSS to detect deceleration of the vehicle, and modulatingwarning lights of the vehicle in response to the vehicle's deceleration.In some embodiments, the VSS emits a periodic function whose frequencycorresponds to the vehicle's speed. For example, some embodiments of thepresent invention use a VSS that outputs a DC pulse with a frequencythat corresponds to the speed of the vehicle. In addition, someembodiments of the present invention use a VSS that outputs an AC sinefunction with a frequency that corresponds to the speed of the vehicle.

In one aspect, the presently claimed invention relates to acommunication system for a vehicle. In some embodiments, a communicationsystem for a vehicle comprises a receiver to receive a signal, sent froma lead vehicle, corresponding to a traveling speed of the lead vehicle,a response device that generates an alert to warn of a change in thetraveling speed of the lead vehicle, and a control device coupled to thereceiver and the response device, wherein the receiver sends a signal tothe control device corresponding to the traveling speed of the leadvehicle and the control device operates the response device in a mannerdependent on the traveling speed of the lead vehicle. In someembodiments the signal comprises one or more of infrared, infraredlaser, radio frequency, wireless, WiFi, and Bluetooth®. In someembodiments the signal corresponds to a deceleration status of the leadvehicle. In further embodiments the signal comprises digitalinformation. In some embodiments the signal is transmitted from analerting device that modulates the signal at a specific frequency whichis received by the receiver which only recognizes the signal at thespecific frequency. In some of these embodiments the specific frequencycomprises 38 KHz. In further embodiments the specific frequencycomprises 100 Hz. In some embodiments the response device generates avisual alert. In some embodiments the response device generates anauditory alert. In further embodiments the alert corresponds to theactual speed of the lead vehicle. In some embodiments the communicationsystem further comprising a speed control system coupled to the controldevice, wherein the control device operates the speed control system ina manner dependent on the traveling speed of the lead vehicle.

In another aspect, a system for communicating the traveling speed of avehicle comprises an alerting device placed in a first vehicle thattransmits a non-visual signal corresponding to a traveling speed of thefirst vehicle, and a receiver placed in a second vehicle that receivesthe non-visual signal sent by the alerting device. In some embodimentsthe non-visual signal comprises one or more of infrared, infrared laser,radio frequency, WiFi, and Bluetooth®. In some embodiments the signalcorresponds to a deceleration status of the first vehicle. In furtherembodiments the signal comprises digital information. In someembodiments the alerting device modulates the signal at a specificfrequency which is received by the receiver which only recognizes thesignal at the specific frequency. In some of these embodiments thespecific frequency comprises 38 KHz. In further embodiments the specificfrequency comprises 100 Hz. In some embodiments the system furthercomprises a response device that generates an alert to warn of a changein the traveling speed of the first vehicle. In some of theseembodiments the response device generates a visual alert. In furtherembodiments the response device generates an auditory alert. In stillfurther embodiments the alert corresponds to the actual speed of thefirst vehicle. In some embodiments the system further comprises acontrol device placed in the second vehicle coupled to a speed controlsystem and the receiver, wherein the receiver sends a signal to thecontrol device corresponding to a change in the traveling speed of thefirst vehicle and the control device operates the speed control systemin a manner dependent on the traveling speed of the first vehicle. Insome embodiments the alerting device and the receiver are installed asaftermarket equipment.

In another aspect, a method of alerting drivers to a change in thetraveling speed of a vehicle comprises determining a traveling speed ofa first vehicle, if the traveling speed has changed, transmitting anon-visual signal from the first vehicle, receiving the non-visualsignal at a second vehicle, and generating an alert at the secondvehicle that the traveling speed of the first vehicle has changed. Insome embodiments the alert correspond to the actual speed of the firstvehicle. In some embodiments the non-visual signal is an infrared signalmodulated at a specific frequency which is received by a receiver placedin the second vehicle which recognizes the signal only at the specificfrequency. In some of these embodiments the specific frequency comprises38 KHz. In further embodiments the specific frequency comprises 100 Hz.In some embodiments the alert is visual. In further embodiments thealert is auditory. In some embodiments the second vehicle furthercomprises a control device coupled to a speed control system and thereceiver, wherein the receiver sends a signal to the control devicecorresponding to the traveling speed of the first vehicle and thecontrol device operates the speed control system in a manner dependenton the traveling speed of the first vehicle.

In a further aspect, a communication system for a vehicle comprises avehicle speed sensor to detect a traveling speed of the vehicle, analerting device that transmits a non-visual signal corresponding to thetraveling speed of the vehicle to a receiver placed in a followingvehicle, and a control device coupled to the vehicle speed sensor andthe alerting device, wherein the vehicle speed sensor sends signals tothe control device and the control device operates the alerting devicein a manner dependent on the traveling speed of the vehicle. In someembodiments the non-visual signal corresponds to a deceleration statusof the vehicle. In some embodiments the non-visual signal comprisesdigital information. In further embodiments the non-visual signalcorresponds to the actual speed of the vehicle. In some embodiments thenon-visual signal is an infrared signal modulated at a specificfrequency which is received by the receiver which recognizes the signalonly at the specific frequency. In some of these embodiments thespecific frequency comprises 38 KHz. In further embodiments the specificfrequency comprises 100 Hz. In some embodiments the non-visual signalcomprises one or more of infrared, infrared laser, radio frequency,wireless, WiFi, and Bluetooth®.

In yet another aspect, a communication system for a vehicle comprises arangefinder to calculate a distance between the vehicle and an object, avehicle speed sensor to sense a speed of the vehicle, a response devicethat generates an alert, and a control device coupled to therangefinder, the vehicle speed sensor, and the response device, whereinthe control device receives a signal from the rangefinder and thevehicle speed sensor and operates the response device in a mannerdependent on the signal received from the range finder and the vehiclespeed sensor. In some embodiments the object is a leading vehicle. Insome of these embodiments the response device generates an alert toindicate an unsafe following distance between the vehicle and theleading vehicle. In further embodiments the response device generates analert to indicate an unsafe closure rate between the vehicle and theleading vehicle. In some embodiments the range finder uses one or moreof infrared, infrared laser, sonar, and radar to calculate the distancebetween the vehicle and an object. In some embodiments the range finderuses trigonometry methods and is one or more of a stadiamettric rangefinder, parallax range finder, and a coincidence range finder. In someembodiments the range finder is pointable in the same direction oftravel as the lead vehicle. In further embodiments the object is afollowing vehicle. In some of these embodiments the response devicegenerates an alert to indicate an unsafe distance between the vehicleand the following vehicle. In further embodiments the response devicegenerates an alert to indicate an unsafe closure rate of the followingvehicle. In some embodiments the range finder is pointable in the samedirection as the following vehicle as the vehicle is making a turn. Insome embodiments the communication system further comprises a speedcontrol system coupled to the control device, wherein the control deviceoperates the speed control system in a manner dependent on the signalreceived from the range finder and the vehicle speed sensor.

In another aspect, a communication system for a vehicle comprises avehicle speed sensor to sense a speed of the vehicle, a warning devicethat generates an alert to warn of the vehicle, and a control devicecoupled to the vehicle speed sensor and the warning device, wherein thevehicle speed sensor sends a signal to the control device correspondingto a speed of the vehicle and the control device operates the warningdevice in a manner dependent on the speed of the vehicle. In someembodiments the vehicle is a motorcycle. In some embodiments the warningdevice flashes a white light. In some embodiments the white lightflashes to a front of the vehicle. In some embodiments the white lightflashes to a side of the vehicle. In further embodiments the white lightflashes to the front and to a side of the vehicle. In some embodimentsthe control device activates the warning device once the vehicle reachesa predetermined speed. In some embodiments the warning devicecontinuously flashes the white light. In further embodiments the warningdevice flashes the white light at a rate correlated to a traveling speedof the vehicle. In further embodiments the communication system for avehicle comprises a rangefinder to calculate a distance between thevehicle and an object, wherein the control device is further coupled tothe rangefinder and further, wherein the control device receives asignal from the rangefinder and the vehicle speed sensor and operatesthe warning device in a manner dependent on the signal received from therange finder and the vehicle speed sensor. In some embodiments theobject is a leading vehicle. In some embodiments the object is one ormore of a stoplight and a stop sign. In further embodiments the objectis an object located to a side of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a single axis accelerometer positioned for measuringlateral acceleration, and included in an accelerometer-gyroscopic sensorin accordance with an embodiment of the present invention.

FIG. 1B illustrates a dual axis accelerometer positioned for measuringvertical and longitudinal acceleration, and included in anaccelerometer-gyroscopic sensor in accordance with an embodiment of thepresent invention.

FIG. 2A illustrates a gyroscope positioned for measuring a heading, andincluded in an accelerometer-gyroscopic sensor in accordance with anembodiment of the present invention.

FIG. 2B illustrates a gyroscope positioned for measuring a lateralinclination, and included in an accelerometer-gyroscopic sensor inaccordance with an embodiment of the present invention.

FIG. 2C illustrates a longitudinal inclination, and included in anaccelerometer-gyroscopic sensor in accordance with an embodiment of thepresent invention.

FIG. 3A is a schematic view illustrating the components of the rear-endcollision avoidance system, warning drivers of a subject vehicle'sdeceleration, in accordance with an embodiment of the present invention.

FIG. 3B illustrates a state machine diagram of the control device inaccordance with some embodiments of the present invention.

FIG. 3C illustrates a state machine diagram of the control device inaccordance with an alternative embodiment of the present invention.

FIG. 4 illustrates a schematic view of an anti-rollover system inaccordance with an embodiment of the present invention.

FIG. 5 illustrates a schematic view of an engine performance monitoringsystem in accordance with an embodiment of the present invention.

FIG. 6 illustrates a schematic view of a suspension and road conditionmonitoring system in accordance with an embodiment of the presentinvention.

FIG. 7 illustrates a navigation system in accordance with an embodimentof the present invention.

FIG. 8 illustrates a schematic view of an anti-rollover system inaccordance with an embodiment of the present invention.

FIG. 9 is a schematic view illustrating the components of the rear-endcollision avoidance system, warning drivers of a subject vehicle'sdeceleration, in accordance with some embodiments of the presentinvention.

FIG. 10 is a schematic view illustrating the components of a vehiclemonitoring system, warning drivers of a subject vehicle's stationarystatus and turning off an idling engine, in accordance with someembodiments of the present invention.

FIG. 11 illustrates a flow chart of a system to automatically turn offan idling engine in accordance with some embodiments of the presentinvention.

FIG. 12 is a schematic view illustrating the components of the rear-endcollision avoidance system, warning drivers of a subject vehicle'straveling speed, in accordance with some embodiments.

FIG. 13 illustrates a flow chart of a system to communicate a travelingspeed of a subject vehicle, in accordance with some embodiments.

FIG. 14 is a schematic view illustrating the components of the rear-endcollision avoidance system, in accordance with some embodiments.

FIG. 15 is a schematic view illustrating the components of acommunication system for a vehicle, in accordance with some embodiments.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 1B and 2C, one embodiment of the present inventionincludes a dual axis accelerometer and an electronic gyroscopepositioned upon a moving body (not shown) having a pitch axis and a yawaxis that form a pitch-yaw plane as illustrated, which attempts to movealong a movement vector orthogonal to the pitch-yaw plane. A first axis,termed the longitudinal axis, of the dual axis accelerometer is placedorthogonal to the plane of the pitch and yaw axes to sense accelerationalong the movement vector. A second axis, termed the vertical axis, ofthe accelerometer is placed parallel with the yaw axis (and thusperpendicular to the movement vector) to sense acceleration along theyaw axis. Thus the two axes of the accelerometer form alongitudinal-vertical plane orthogonal to the pitch-yaw plane.

The gyroscope in FIG. 2C is mounted parallel to thelongitudinal-vertical plane of the accelerometer and thus is also alonga plane perpendicular to the pitch-yaw plane of the moving body. Thisconfiguration allows it to sense an inclination of the movement vectorof the moving body relative to the gravitational acceleration acting onthe body.

In some embodiments of the present invention, an accelerometer is usedto detect additional types of movement. The orientation shown in FIG. 1Aallows for detection of lateral acceleration. In FIG. 1A, a single axisaccelerometer configured with a first axis, termed the lateral axis,parallel to the pitch axis senses lateral acceleration of the body, e.g.acceleration in a plane orthogonal to the longitudinal-vertical plane.

When the body does undergo a lateral acceleration, its actual movementis no longer along the desired movement vector. Thus, during lateralacceleration, another gyroscope can be included to sense the inclinationof the component of the actual movement vector that lies along thelateral axis. FIG. 2B depicts a gyroscope configured parallel to thepitch-yaw plane and thus configured to detect an inclination of thecomponent of movement that lies along the lateral axis, termed thelateral inclination of the body.

In some embodiments, the system also includes another gyroscope that isconfigured parallel to the lateral-longitudinal plane (in which alldesirable movement vectors will lie), to detect a heading of the body.This additional gyroscope is required for those embodiments that supplysupplemental data to navigation systems.

The embodiments of the present invention include logic circuitsconfigured to receive signals of acceleration along the lateral,longitudinal, and vertical axes, as well as of the lateral andlongitudinal inclinations and the heading, if necessary and to processthese signals to produce a variety of output signals indicatingcharacteristics of the moving body's movement. In some embodiments,these include: absolute longitudinal acceleration (both positive andnegative), absolute vertical acceleration (both positive and negative),absolute lateral acceleration (both positive and negative), heading, andactual speed.

Though accelerometers are inherently stable, and especially so wheninternally temperature compensated, gyroscopes, both mechanical andelectronic, can suffer from instability and drift. Because of thesedrift characteristics, gyroscopes typically require periodicauto-zeroing or re-referencing to provide reliable output.

In some embodiments of the present invention, a method of detecting anabsolute deceleration includes steps of re-referencing. This task isable to be accomplished using signals from the accelerometers, but inother embodiments use a Hall effect, electronic or other type ofcompass.

Re-referencing is able to take place periodically; for systems usingHall effect or some other independent compass, the systems simplyre-reference at specified heading or timing intervals. However, in someembodiments, systems that use accelerometer data for re-referencing aremore careful. When stationary, any signal from the accelerometer isessentially representative of the earth's gravity, this signal canprovide an initial reference for any gyroscopes included in the presentinvention, which is able to take place prior to movement of the body.

Once the body has begun moving, without periodic re-referencing, thegyroscope output can become unreliable. The present invention teachesseveral methods of re-referencing during travel. Some of these are onlyapplicable to travel that includes periodic stops. For example, thevertical or lateral axis accelerometers can be used to detect whetherthe body is stopped. When it is stopped, the signal from thelongitudinal axis of the accelerometer can be used to re-reference thegyroscope. Further, at any point during travel when no acceleration hasbeen detected for a predetermined period of time the gyroscope can bere-referenced. In this way repeated referencing can occur even duringextended travel without any stops.

In some embodiments, the present invention is implemented in a vehicle,and the following embodiments of the present invention are describedrelative to a vehicle. However, the methods and systems taught by thepresent invention can be implemented in a wide variety of moving bodiesother than vehicles.

Example 1 Rear End Collision Avoidance

FIG. 3A is a schematic view illustrating the components of the rear-endcollision avoidance system 300, warning drivers of a subject vehicle'sdeceleration, in accordance with one embodiment of the presentinvention. The rear-end collision avoidance system 300 comprises anaccelerometer-gyroscopic sensor 310, a braking system engagementdetector 320, a throttle engagement detector 330, and a control device340. The accelerometer-gyroscopic sensor 310 is coupled to the controldevice 340, detects an absolute longitudinal deceleration of thevehicle, and sends a signal to the control device 340. The brakingsystem engagement detector 320 is also coupled to the control device340, detects any engagement of the braking system of the vehicle, andsends a signal to the control device 340. The throttle engagementdetector 330 is also coupled to the control device 340 and detectsengagement of the throttle. In alternative embodiments, the presentinvention also includes additional input devices, such as a clutchengagement detector configured to relay a clutch status to the controldevice 340. Next, the control device 340 processes the input signals itreceives from the accelerometer-gyroscopic sensor 310, the brakingsystem engagement detector 320, and the throttle engagement detector 330and decides whether to activate an alerting device of the vehicle. Insome embodiments the control device 340 only activates an alertingdevice if the vehicle is throttled down but not braking. In someembodiments, the control device 340 activates the alerting device onlyif the absolute longitudinal deceleration is non-zero. In oneembodiment, the communication system further comprises an alertingdevice activation circuit 350, wherein the control device 340 is coupledto and sends signals to the alerting device activation circuit 350,which activates an alerting device based on a signal from the controldevice 340.

In some other embodiments, input from a vehicle speed sensor (VSS) isused to perform a similar function. FIG. 9 is a schematic viewillustrating the components of the rear-end collision avoidance system900, warning drivers of a subject vehicle's deceleration, in accordancewith one embodiment of the present invention. The rear-end collisionavoidance system 900 comprises a vehicle speed sensor 910, anacceleration monitoring system 915, a braking system engagement detector920, and a control device 940. It can also include a throttle engagementdetector 930.

The vehicle speed sensor 910 is coupled to the acceleration monitoringsystem 915, which is coupled to the control device 940. The vehiclespeed sensor 910 detects a speed of the vehicle and emits a periodicfunction with a frequency that is correlated to the speed of thevehicle. The acceleration monitoring system 915 uses variations in theperiodic function to calculate the acceleration (or deceleration) of thevehicle. The acceleration monitoring system 915 sends a signal to thecontrol device 940 that represents deceleration of the vehicle. Thebraking system engagement detector 920 is also coupled to the controldevice 940, detects any engagement of the braking system of the vehicle,and sends a signal to the control device 940. If present, the throttleengagement detector 930 is also coupled to the control device 940 anddetects engagement of the throttle. In alternative embodiments, thepresent invention also includes additional input devices, such as aclutch engagement detector configured to relay a clutch status to thecontrol device 940. Next, the control device 940 processes the inputsignals it receives from the acceleration monitoring system 915, thebraking system engagement detector 920, and the throttle engagementdetector 930 and decides whether to activate an alerting device of thevehicle. In some embodiments the control device 940 only activates analerting device if the vehicle is throttled down but not braking. Insome embodiments, the control device 940 activates the alerting deviceonly if the absolute longitudinal deceleration is non-zero. In oneembodiment, the communication system further comprises an alertingdevice activation circuit 950, wherein the control device 940 is coupledto and sends signals to the alerting device activation circuit 950,which activates an alerting device based on a signal from the controldevice 940.

Some embodiments use a microprocessor or micro-controller as theacceleration monitoring system 915 to measure pulse width differentialsbetween consecutive pulses. If the periodic function produced by the VSSis a DC pulse, only one wire is needed to interface with the VSS 910. Ifthe periodic function is an AC sine wave two wires are used.

The functions of an embodiment illustrated with reference to FIG. 9 areperformed in a module that contains various discrete electroniccomponents involved in signal conditioning as well as a microprocessoror microcontroller, which would actually do the computations. Theseinclude one or more of the following: a microprocessor, interpreter,voltage regulator, RAM, EEPROM, resonator and communication port andcircuitry along with various filtering and voltage protection circuitry.In some embodiments, the module is capable of accurately measuring andcomparing pulse widths of 1 millionth of a second or less andfrequencies of zero (0) to mega hertz all within time frames of micro tomilliseconds. The present invention can be implemented in an analog,electromechanical, or a digital circuit including programmable elements.

In addition, in some embodiments the various embodiments described aboveare implemented in a module that includes a separate aftermarket VSS.These embodiments are advantageous when used to retrofit older vehiclesthat do not come with a VSS as original equipment.

In addition, some embodiments use an aftermarket VSS, even on newervehicles. For example, one such VSS comprises a sensor configured todetect rotation of the universal joint of a motor vehicle.

In this embodiment, a sensor is mounted on either the rear-end housingor on the back end of the transmission and where the sensor ispositioned over the universal joint. The sensor would not be in contactwith the spinning universal joint but in close proximity, e.g. ⅛ or ¼inch air gap.

In some embodiments, the sensor is configured to sense ferrous metal.Thus, there is no need to affix anything to the actual spinninguniversal joint. Universal joint typically have four protrusions. Thesensor is optionally configured to sense either two or four of theprotrusions. The resultant signal represents variations in the magneticflux field produced by the sensor each time a protrusion passes throughthe magnetic field.

One type of sensor used in some embodiments of the present inventioncomprises a coil with or without a core. When a voltage is applied tothe coil, a magnetic flux field is produced around the coil. If aferrous metal object passes through that field it robs just a little ofthe power (which is stored in the field) resulting in a change in thecurrent and voltage within the coil and conductor feeding the coil. Thissignal is then used to produce a square wave.

The embodiments of the present invention include input devices. Thosementioned above include braking system engagement detectors, throttleengagement detectors, the accelerometer-gyroscopic sensor, andVSS/acceleration monitoring systems. In alternative embodiments, thepresent invention also includes additional input devices, such as aclutch engagement detector configured to relay a clutch status to thecontrol device.

The embodiments of the presently claimed invention include alertingdevices. In some embodiments, an alerting device comprises lamps on thevehicle that are capable of flashing and emitting visible light. In oneaspect, the lamps of the alerting device flash only at a constant rate,while in another aspect the lamps flash at a variable rate, and furtherwherein the control device is configured to flash the lamps at a ratecorrelated to a rate of deceleration. In some embodiments, the lamps areone of the following: conventional signaling lamps and conventionalbrake lamps. However, in another embodiment, the alerting device is aradio frequency (RF) transmitter capable of directing RF signals fromthe rear of the vehicle to a following vehicle. In other embodiments,the alerting device uses other types of signals.

For example, in some other embodiments, the signaling lamps usedcomprise bi-color light emitting diodes (LED). In these embodiments, thebi-color LEDs change color depending on the polarity of the current usedto energize them. Thus, the control device in these embodiments isconfigured to provide current to the bi-color LEDs with a polarity thatvaries depending on the signal to be sent. For example, in oneembodiment the control device leaves the bi-color LEDs un-energized whenno deceleration is occurring and the brakes are not engaged, provides acurrent with a polarity to cause the bi-color LEDs to emit a yellowlight upon deceleration, and to provide a current with a polarity tocause the bi-color LEDs to emit a red light upon braking.

When used in this patent, the terms “conventional signaling lamps” and“conventional brake lamps” refer to signaling or brake lamps included onmotor vehicles during their original manufacture. The present inventionalso contemplates signaling by using after-market devices that areattached to a vehicle in addition to conventional signaling and brakelamps.

A communication system can be embodied as an after-market add-on productor as an original vehicle system. These embodiments include differenttypes of controllers. In some embodiments of an add-on system, a controldevice does not interfere with the existing brake lamp systemcontroller. The control device communicates with the brake lamps in asubstantially separate manner from the existing brake lamp controlsystem. Control devices used in the present invention could includerelays, switches or micro controllers. In one aspect, an aftermarketsystem can continuously power the alerting device activation circuitwithout need of an intermediate control device.

However, in an original equipment system, a communication system inaccordance with the present invention is able to include a controldevice that further comprises a control system for the conventionalbrake lamp system, whereby the communication system is an integratedcontrol and circuitry system for all brake lamps. In this aspect, asingle control system accomplishes the tasks of conventional brakesignaling and the signaling described in the present invention.

During operation, the communications system of the present inventionuses information from the various input devices to determine a manner inwhich to operate an alerting device. In one aspect, the communicationssystem continuously modulates the alerting device based on theaccelerometer-gyroscopic sensor's input so long as the throttle isdisengaged, regardless of braking system status. In another aspect, oncethe braking system is engaged, the communications system activates thealerting device continuously until disengagement of the braking system,whereupon the communications system once again considers throttle andthe accelerometer-gyroscopic sensor's input in choosing a manner inwhich to operate the alerting device. In a third aspect, where aconventional braking system exists separately from a communicationssystem as described in the present invention, the control devicedeactivates in response to braking system engagement and reactivatesupon braking system disengagement. In some embodiments, the controldevice receives input in cycles and makes a determination for operationof the alerting device within each cycle.

In one embodiment, the control device 940 takes input from theacceleration monitoring system 915, the braking system engagementdetector 920, and the throttle engagement detector 930 in cycles thatare substantially continuous in time. In some embodiments, for eachcycle, the control device 940 enters one of four states: I) it does notactivate an alerting device for the entirety of the cycle, II) itactivates an alerting device for the entirety of the cycle, III) itactivates an alerting device at least once for a period of time that isshort relative to the duration of the cycle; or IV) it activates analerting device multiple times during the cycle.

FIG. 3B illustrates an embodiment in which these four output states arehandled. A state machine 301, included in a control device in accordancewith the present invention, takes five possible input states, for fourof them throttle status is not considered: 1) brake pedal is notdepressed, deceleration is not detected; 2) brake pedal is notdepressed, deceleration is detected; 3) brake pedal is depressed,deceleration is detected; or 4) brake pedal is depressed, decelerationis not detected. State 5) only occurs if the throttle is disengaged, andif the brake pedal is not depressed. Input state 1 corresponds to outputstate I, input state 2 corresponds to output state III, input states 3and 5 correspond to output state II, and input state 4 corresponds tooutput state IV.

Transitions between all input states are handled and every transition isa plausible outcome of a braking or acceleration event. For example, adriver disengaging the throttle pedal causes a transition from state 1to state 5. In the first cycle detecting state 5, the brake lamps areilluminated. Once a required level of deceleration is detected, atransition from state 5 to state 2 occurs. In the first cycle detectingstate 2, the brake lamps are flashed, or another alerting device isactivated, corresponding to output state III. A transition from state 1directly to state 2 can occur when beginning ascent of a steep grade:the throttle is engaged, the brake pedal is disengaged but the vehiclebegins to decelerate.

If the driver engages the throttle again, or in the case of an ascent,increases the throttle, a transition from state 5 to state 1, or state 2to state 1, occurs. If the driver subsequently depresses the brakepedal, a transition from state 2, or state 5, to state 3 occurs. Whilethe brake pedal is depressed, state II output keeps the brake lampsilluminated. Furthermore, while the brake pedal is depressed, atransition from state 3 to state 4 may occur. In this embodiment, instate 4 the lamps are flashed at an increased rate. Whenever the brakepedal is depressed, state II or IV output occurs andaccelerometer-gyroscopic sensor data is effectively ignored. When thebrake pedal is released, one of input state 1, input state 2, and inputstate 5 are entered.

A transition from input state 3 to 2 corresponds to tapping or pumpingthe brake pedal. Depending on the length of time a cycle comprises, aresidual brake lamp flash may occur. Transitions from input states 3 or4 to state 1 correspond respectively to accelerating from a rolling stopon a hill, or rolling forward downhill. A transition from input state 4to 2 could arise when rolling down a hill backwards, for example at astoplight on a hill. This points to another feature of the currentsystem—providing a warning for rollback.

In the alternative embodiment illustrated in FIG. 3C, a state machine301′ included in a control device in accordance with the presentinvention, the system only considers the first three states. The statemachine 301′ takes four possible input states: 1) brake pedal is notdepressed, deceleration is not detected; 2) brake pedal is notdepressed, deceleration is detected; 3) brake pedal is depressed,deceleration is detected; or 4) brake pedal is depressed, decelerationis not detected. Input state 1 corresponds to output state I, inputstate 2 corresponds to output state III, and input states 3 and 4correspond to output state II.

Transitions between all input states are handled and every transition isa plausible outcome of a braking or acceleration event. For example, adriver taking his or her foot off the accelerator pedal causes atransition from state 1 to state 2. In the first cycle detecting state2, the brake lamps are flashed, or other alerting means are activated,corresponding to output state III. This transition from state 1 to state2 also occurs when beginning ascent of a steep grade: the accelerator isdepressed, the brake pedal is disengaged but the vehicle begins todecelerate. If the driver presses the accelerator again, or in the caseof an ascent, further depresses the accelerator, a transition from state2 to state 1 occurs. If the driver subsequently depresses the brakepedal, a transition from state 2 to state 3 occurs. While the brakepedal is depressed, state II output keeps the brake lamps illuminated.Furthermore, while the brake pedal is depressed, a transition from state3 to state 4 may occur. In this embodiment, such a transition results inno change in output. Whenever the brake pedal is depressed, state IIoutput occurs and accelerometer-gyroscopic sensor data is effectivelyignored. When the brake pedal is released, either input state 1 or inputstate 2 is entered.

In some embodiments a transition from input state 3 to 2 corresponds totapping or pumping the brake pedal. Depending on the length of time acycle comprises, a residual brake lamp flash may occur. Transitions frominput states 3 or 4 to state 1 correspond respectively to acceleratingfrom a rolling stop on a hill, or rolling forward downhill. A transitionfrom input state 4 to 2 could arise when rolling down a hill backwards,for example at a stoplight on a hill. This points to another feature ofthe current system—providing a warning for rollback.

In some embodiments, it is less desirable to utilize flashing lamps or avisual signal as the alerting device to indicate a change in thetraveling speed of a lead vehicle. For example, in military operations,border patrol, and law enforcement applications it may be desirable totravel in a covert lights-off mode. In such applications, it isdesirable to communicate information such as vehicle speed, braking anddeceleration from a leading vehicle to a following vehicle in anon-visual manner. Thus, changes in traveling speed may be communicatedfrom the alerting device located in a lead vehicle directly to areceiver located in a following vehicle in a discrete, non-visualmanner.

FIG. 12 is a schematic view illustrating the components of a rear-endcollision avoidance system 1200, warning drivers of a vehicle'straveling speed, in accordance with some embodiments. As shown in FIG.12, the rear-end collision avoidance system 1200 comprises a receiver1255, a control device 1245, and a response activation circuit 1275. Asshown in FIG. 12, in some embodiments, the rear-end collision avoidancesystem 1200 also comprises a speed control system activation circuit1265. The rear-end collision avoidance system 1200 of FIG. 12 works inconjunction with the rear end collision avoidance system 900 describedin reference to FIG. 9. Particularly, the rear-end collision avoidancesystem 1200 is implemented within a following vehicle and receives asignal sent from the alerting device of a lead vehicle.

As described above, in some embodiments, the alerting device isconfigured to flash conventional signaling or brake lamps at a ratecorrelated to a rate of deceleration. Additionally, in some embodiments,the alerting device is a RF transmitter capable of directing RF signalsfrom the rear of the vehicle to the following vehicle. In furtherembodiments, the alerting device is a transmitter that directs awireless signal to the following vehicle. In some of these embodiments,the signal corresponds to the traveling speed of the vehicle. In furtherembodiments, the signal corresponds to a deceleration status of thevehicle. In some embodiments, the wireless signal is one or more of aninfrared signal, WiFi signal, and a Bluetooth® signal. However, thealerting device is able to transmit any other wireless signal as knownin the art. In further embodiments, the alerting device is a rear facingwarning device and transmits infrared signals such as for use in covertoperations as described above. In some embodiments, the alerting devicetransmits infrared laser. In further embodiments, the alerting devicetransmits a signal which is modulated to carry digital information.

In some embodiments, the signal sent by the alerting device is adiscrete signal so that the receiver 1255 is able to differentiate theintended signal from other randomly occurring signals. In theseembodiments, the receiver 1255 is configured to receive only a specificsignal. For example, in some embodiments, the alerting device modulatesan infrared signal at 38 KHz and the receiver 1255 is configured toreceive an infrared signal only at 38 KHz. In other embodiments, thealerting device modulates an infrared signal at a lower rate such as 100Hz. Particularly, the alerting device is able to transmit and thereceiver 1255 is able to receive signals at any frequency as known inthe art. Additionally, in some embodiments, the signal is an infraredLED. In these embodiments, the signal is only received by an enhancedreceiver that is capable of viewing infrared LED.

As shown in FIG. 12, the rear-end collision avoidance system 1200comprises a control device 1245 coupled to a response device activationcircuit 1275. As described above, the alerting device sends a signal tothe receiver 1255 according to the traveling speed of the lead vehicle.In some embodiments, the alerting device sends a signal to the receiver1255 that the lead vehicle is decelerating. After receiving a signalfrom the alerting device, the receiver 1255 sends a signal to thecontrol device 1245 corresponding to the traveling speed of the leadvehicle and the control device 1245 sends a signal to the responsedevice activation circuit 1275, which activates a response device in amanner dependent on the signal from the control device 1245. Forexample, in some embodiments, the response device generates an alertannouncing, “SLOWING TRAFFIC AHEAD . . . SLOWING TRAFFIC AHEAD, or . . .STOPPED TRAFFIC AHEAD . . . STOPPED TRAFFIC AHEAD. In some embodiments,the response device generates a visual alert which appears on a screen.In some embodiments, the response device generates an auditory alertthrough a Bluetooth® device or speakers. In some embodiments, theresponse device generates an alert that indicates the actual speed ofthe lead vehicle. The alert generated by the response device isdependent on the signal received from the control device 1245 and iscommunicated from the response device to the driver of the followingvehicle.

As also shown in FIG. 12, in some embodiments, the rear-end collisionavoidance system 1200 comprises a speed control system activationcircuit 1265 coupled to the control device 1245. In these embodiments,after receiving a signal from an alerting device, the receiver 1255sends a signal to the control device 1245 corresponding to the travelingspeed of the lead vehicle and the control device 1245 sends a signal tothe speed control system activation circuit 1265, which is able tocontrol the speed of the following vehicle in a manner dependent on thesignal from the control device 1245. For example, in some embodiments,the control device 1245 activates the speed control system activationcircuit 1265 to activate the braking system in order to slow thefollowing vehicle to a speed equal to the lead vehicle. In someembodiments, the control device 1245 activates the speed control systemactivation circuit 1265 to activate the braking system in order tomaintain a safe distance between the following vehicle and the leadvehicle. In further embodiments, the control device 1245 activates thespeed control system activation circuit 1265 to increase the speed ofthe following vehicle in order to maintain a consistent distance betweenthe following vehicle and the lead vehicle such as while travelingwithin a convoy.

In some embodiments, the rear-end collision avoidance system 1200comprises a speed control system activation circuit 1265 and a responsedevice activation circuit 1275 coupled to the control device 1245. Insome embodiments, the rear-end collision avoidance system 1200 isinstalled at the factory. In other embodiments, the rear-end collisionavoidance system 1200 is installed as aftermarket equipment. In someembodiments, the rear-end collision avoidance system 1200 is implementedon one or more of an automobile, off road vehicle, and motorcycle. Insome embodiments the rear-end collision avoidance system 1200 isimplemented on a bicycle. The rear end collision avoidance system 900and the rear-end collision avoidance system 1200 communicate adeceleration status of a lead vehicle to a following vehicle withoutrelying on the conventional stop lamps of the lead vehicle.

FIG. 13 illustrates a flow chart of a system to communicate adeceleration status of a subject vehicle's deceleration, in accordancewith some embodiments of the present invention.

As shown in FIG. 13, at the step 1304 a traveling speed of a firstvehicle is determined, as described above. If it is determined that thetraveling speed of the first vehicle has changed, then at the step 1306,an alerting device of the first vehicle transmits a signal to a secondvehicle, such as a following vehicle. As described above, in someembodiments, the signal is one or more of an infrared signal, WiFisignal, and a Bluetooth® signal. At the step 1308, a receiver receivesthe transmitted signal from the alerting device. Upon receiving thesignal from an alerting device, the receiver sends a signal to a controldevice corresponding to the traveling speed of the first vehicle and thecontrol device sends a signal to a response device activation circuit,which at the step 1310 activates a response device in a manner dependenton the signal from the control device. In some embodiments, the signaland the response correspond to the deceleration status of the vehicle.In some embodiments, the control device also sends a signal to a speedcontrol system activation circuit, which slows or increases the speed ofthe second vehicle in a manner dependent on the signal from the controldevice.

In use, the communication system 1200 enables an alerting device placedwithin a leading vehicle to transmit information to a receiver placedwithin a following vehicle in a non-visual manner. In doing so the leadvehicle is able to transmit information such as actual speed, brakingstatus, and deceleration discretely and without interference. Thecommunication system has the advantage of allowing users to transmit andreceive vehicle speed information in a more direct manner without usingconventional brake lamps or other conventional stop lamps. Additionally,the communication system enables a following vehicle to maintain aconsistently safe distance from a leading vehicle. Accordingly, thecommunication system 1200 has many advantages.

In further embodiments, it may be desirable to implement thecommunication system completely within one vehicle. In theseembodiments, information such as vehicle speed, deceleration, brakingand distance of a following vehicle may be communicated in a mannerdependent on the position of a lead vehicle and the speed of a followingvehicle. In calculating a distance between the vehicle and an objectsuch as another vehicle, a communication system is able to activate awarning to indicate an excessive closure rate or an unsafe followingdistance before receiving a warning from the lead vehicle or as asubstitute for receiving a warning from the lead vehicle. Alternatively,the communication system is able to activate a warning to indicate anexcessive closure rate or an unsafe following distance of a followingvehicle.

FIG. 14 illustrates a communication system for a vehicle 1400 inaccordance with further embodiments. The communication system 1400comprises a range finder 1485, a vehicle speed sensor (VSS) 1410, acontrol device 1445, and a response device activation circuit 1475. Insome embodiments, the communication system further comprises a speedcontrol system activation circuit 1465. The VSS 1410 emits a periodfunction with a frequency corresponding to the speed of the vehicle andsends a signal to the control device 1445. The range finder 1485calculates a distance from the vehicle to an object and sends a signalto the control device 1445. Based upon the signal from the VSS 1410 andthe range finder 1485 the control device 1445 sends a signal to theresponse device activation circuit 1475, which operates a responsedevice in a manner dependent upon the signal sent from the controldevice 1445.

In some embodiments, the range finder 1485 calculates the distance froma following vehicle to a leading vehicle. In some embodiments, the rangefinder 1485 calculates the distance between the following vehicle andthe leading vehicle by utilizing a set of known distances and targetsizes. For example, in some embodiments the range finder 1485 calculatesthe distance between a following vehicle and a lead vehicle by using thelicense plate of the lead vehicle, which is a standard size. In someembodiments, the distance is measured using sonar, laser and radar. Insome embodiments. the distance is calculated using trigonometry methodssuch as with a stadiametric range finder, parallax range finder, and acoincidence range finder. However, the range finder is able to calculatethe distance between the following vehicle and the lead vehicle by anymethod as known in the art. In some embodiments, the range finder 1485is pointable in the same direction as a lead vehicle that is making aturn. In these embodiments, the range finder 1485 is able to maintainfocus on the leading vehicle for a longer period of time as the leadingvehicle turns.

In some embodiments, after calculating the distance from a followingvehicle to a leading vehicle, the range finder 1485 sends a signal tothe control device 1445 that corresponds to that distance. As describedabove, the VSS 1410 also sends a signal to the control device 1445corresponding to the speed of the vehicle. After receiving the signalfrom the range finder 1485 and the VSS 1410, the control device 1445sends a signal to the response device activation circuit 1475. Thesignal sent by the control device 1445 to the response device activationcircuit 1475 is dependent upon the signal from the range finder 1485 andthe VSS 1410.

In some embodiments, the signal sent by the control device 1445 to theresponse device activation circuit 1475 is dependent upon whether thefollowing vehicle is following the leading vehicle at a safe distance.In these embodiments, the safe following distance is directlyproportional to the rate of speed of the vehicle. For example, if ittakes a vehicle approximately 217 feet to stop when traveling 55 milesper hour (mph) and 315 feet to stop when traveling 70 mph then the safedistance could be at least 217 feet at 55 mph and at least 315 feet at70 mph. Thus, if the control device 1445 receives a signal correspondingto a speed of 55 mph from the VSS 1410 and signal corresponding to adistance of less than 217 feet from the range finder, then the controldevice 1445 sends a signal to the response device activation circuitwhich activates the response device. For example, in some embodiments,the response device generates an alert announcing, “YOU HAVE ENCROACHEDON THE SAFE SEPARATION ZONE.”

In further embodiments, the response device generates an alertindicating an excessive closure rate of the following vehicle withrespect to the leading vehicle. In some embodiments, the response devicegenerates an alert indicating that the following vehicle is travelingtoo close to the lead vehicle based on its current speed. Alternatively,the response device generates an alert indicating that the followingvehicle is traveling too far from the lead vehicle based on its currentspeed. In further embodiments, the response device generates an alertannouncing, “SLOWING TRAFFIC AHEAD . . . SLOWING TRAFFIC AHEAD, or . . .STOPPED TRAFFIC AHEAD . . . STOPPED TRAFFIC AHEAD.” As described above,in some embodiments, the response device generates a visual alert whichappears on a screen. In some embodiments, the response device generatesan auditory alert through a Bluetooth® device or speakers. In furtherembodiments, the response device generates an alert that indicates thedistance between the following vehicle and a leading vehicle.

In still further embodiments, the range finder 1485 calculates thedistance from a lead vehicle to a following vehicle. In someembodiments, the range finder 1485 calculates the distance between theleading vehicle and the following vehicle by utilizing a set of knowndistances and target sizes. For example, in some embodiments the rangefinder 1485 calculates the distance between a leading vehicle and afollowing vehicle by using the front license plate of the followingvehicle, which is a standard size. In some embodiments, the distance ismeasured using sonar, laser and radar. In some embodiments. the distanceis calculated using trigonometry methods such as with a stadiametricrange finder, parallax range finder, and a coincidence range finder.However, the range finder is able to calculate the distance between thefollowing vehicle and the lead vehicle by any method as known in theart. In some embodiments, the range finder 1485 is pointable in the samedirection as a following vehicle as the lead vehicle is making a turn.In these embodiments, the range finder 1485 is able to maintain focus onthe following vehicle for a longer period of time as the leading vehicleturns.

In some embodiments, after calculating the distance from a leadingvehicle to a following vehicle, the range finder 1485 sends a signal tothe control device 1445 that corresponds to that distance. As describedabove, the VSS 1410 also sends a signal to the control device 1445corresponding to the speed of the vehicle. After receiving the signalfrom the range finder 1485 and the VSS 1410, the control device 1445sends a signal to the response device activation circuit 1475. Thesignal sent by the control device 1445 to the response device activationcircuit 1475 is dependent upon the signal from the range finder 1485 andthe VSS 1410.

In some embodiments, the signal sent by the control device 1445 to theresponse device activation circuit 1475 is dependent upon whether thefollowing vehicle is following the leading vehicle at a safe distance.As described above, in these embodiments, the safe following distance isdirectly proportional to the rate of speed of the vehicle. In someembodiments, the response device generates an alert announcing, “AFOLLOWING VEHICLE HAS ENCROACHED ON THE SAFE SEPARATION ZONE.”

In further embodiments, the response device generates an alertindicating an excessive closure rate of the following vehicle withrespect to the leading vehicle. In some embodiments, the response devicegenerates an alert indicating that the following vehicle is travelingtoo close to the lead vehicle based on its current speed. In someembodiments, the response device generates a visual alert which appearson a screen. In some embodiments, the response device generates anauditory alert through a Bluetooth® device or speakers. In furtherembodiments, the response device generates an alert that indicates thedistance between the following vehicle and a leading vehicle. In someembodiments, the communication system further comprises an alertingdevice, as described above. In these embodiments, the alerting devicegenerates an alert based on a position of the following vehicle, as alsodescribed above. In some embodiments, the alerting device generates avisual alert. In some embodiments, the alerting device transmits asignal to a receiver placed within the following vehicle.

As also shown in FIG. 14, in some embodiments, the communication system1400 comprises a speed control system activation circuit 1465 coupled tothe control device 1445. In these embodiments, after receiving a signalfrom the VSS 1410 and the range finder 1485, the control device 1445sends a signal to the speed control system activation circuit 1465,which is able to control the speed of the vehicle in a manner dependenton the signal from the control device 1245. For example, in someembodiments, the control device 1445 activates the speed control systemactivation circuit 1465 to activate the braking system in order to slowthe vehicle in order to increase the space between the vehicle and alead vehicle. In some embodiments, the control device 1445 activates thespeed control system activation circuit 1465 to activate the brakingsystem in order to maintain a safe distance between the followingvehicle and the lead vehicle. In further embodiments, the control device1445 activates the speed control system activation circuit 1465 toincrease the speed of the following vehicle in order to maintain aconsistent distance between the following vehicle and the lead vehiclesuch as while traveling within a convoy. In still further embodiments,the control device 1445 activates the speed control system activationcircuit 1465 to increase the speed of the leading vehicle based on anexcessive closure rate of a following vehicle.

In some embodiments, the communication system 1400 comprises a speedcontrol system activation circuit 1465 and a response device activationcircuit 1475 coupled to the control device 1445. In some embodiments,the communication system 1400 is installed at the factory. In otherembodiments, the communication system 1400 is installed as aftermarketequipment. In some embodiments, the communication system 1400 isimplemented on one or more of an automobile, off road vehicle, andmotorcycle. In some embodiments the communication system 1400 isimplemented on a bicycle.

In use, the communication system 1400 provides a warning whichsupplements conventional warning systems and indicates possible unsafedriving conditions or slowing traffic. By warning of an excessiveclosure rate and an unsafe following distance, the speed of a vehiclemay be increased or decreased in order to make driving conditions safe.In addition, in some embodiments, the communication system 1400 has theadvantage of generating a warning which is tailored to the specificspeed of the vehicle and the ideal stopping distance at that speed.Moreover, in some embodiments, by implementing the system entirelywithin one vehicle, the vehicle is not dependent upon other warningsystems in the event of a malfunction or failure of those systems.

In further embodiments, it is desirable to implement a communicationsystem within a vehicle. In these embodiments information such as thespeed and the location of the vehicle may be communicated by flashing alight toward the front or a side of the vehicle. Consequently, thevehicle is more easily seen as it approaches another vehicle or as thevehicle enters and travels through an intersection.

FIG. 15 is a schematic view illustrating the components of acommunication system 1500 for a vehicle in accordance with someembodiments. As shown in FIG. 15, the communication system 1500comprises a vehicle speed sensor (VSS) 1510, a control device 1545, anda warning device activation circuit 1595. The VSS emits a periodicfunction with a frequency corresponding to a speed of the vehicle andsends a signal to the control device 1545. The control device 1545processes the signal it receives from the VSS 1510 and determineswhether to activate a warning device. The control device 1545 is coupledto and sends a signal to the warning device activation circuit 1595,which activates the warning device in a manner based on a signal fromthe control device 1545.

In some embodiments the control device 1545 sends a signal to thewarning device activation circuit 1595 to activate a warning deviceafter the vehicle reaches a predetermined rate of speed. For example, insome embodiments the control device 1545 sends a signal to the warningdevice activation circuit 1595 when the vehicle reaches a speed of 35miles per hour. In some embodiments, the warning device comprises a lampwhich emits a white light. In some embodiments the lamp faces towards afront of the vehicle. In some embodiments the lamp faces toward a sideof the vehicle. In further embodiments the communication system 1500comprises a plurality of lamps which face to the front and a side of thevehicle. However, as will be apparent to someone of ordinary skill inthe art, the lamps are able to face in any direction as known in theart. In some embodiments the lamp flashes at a constant rate, while inanother aspect the lamp flashes at a variable rate. Additionally, insome embodiments the lamp flashes at a rate correlated to a rate ofspeed of the vehicle. For example, in some embodiments the warningdevice flashes the light at an increasingly rapid rate as the vehiclespeeds up. In some embodiments the vehicle is a motorcycle.

As further shown in FIG. 15, in some embodiments the communicationsystem 1500 further comprises a rangefinder 1585. In these embodiments,the rangefinder 1585 calculates a distance from the vehicle to an objectand sends a signal to the control device 1545. The rangefinder 1585 isable to calculate the distance from the vehicle to an object in a manneras described above. Based upon the signal from the VSS 1510 and therangefinder 1585 the control device 1545 sends a signal to the warningdevice activation circuit 1595, which operates the warning device in amanner dependent on the signal from the control device 1545.

In some embodiments the rangefinder 1585 calculates the distance fromthe vehicle to a leading vehicle. Thus, as described above the controldevice 1545 is able to send a signal to the warning activation circuit1595 which activates the warning device based upon the speed of thevehicle and the distance of the vehicle from the leading vehicle. Infurther embodiments the rangefinder 1585 is pointable in an upward or adiagonally upward direction. In these embodiments the rangefinder 1585is able to calculate the distance between a vehicle and an object suchas an overhead stoplight or a stop sign. Consequently, in someembodiments the control device 1545 is able to send a signal to thewarning activation circuit 1595 which activates the warning device whenthe vehicle is a certain distance from an intersection. For example, thewarning device is able to flash when the vehicle is a certain distancefrom an intersection so that the vehicle is more easily seen as thevehicle travels through the intersection. In further embodiments therangefinder 1585 is pointable in a direction to a side of the vehicle.Thus, in some embodiments the control device 1545 is able to send asignal to the warning activation circuit 1595 which activates thewarning device as the vehicle enters an area of congestion or an areawhere the vehicle is likely to encounter turning automobiles.

In use, the communication system 1500 provides a warning system whichsupplements a conventional warning system of a vehicle. By communicatinga position of the vehicle to the front and/or a side of the vehicle, thecommunication system 1500 is able to communicate the vehicle's positionto other vehicles who may not directly see the vehicle. In this manner,the vehicle is able to communicate a warning to side traffic as itapproaches an intersection. Additionally, the vehicle is able tocommunicate its position as it approaches another vehicle from the rear.Accordingly, by flashing a white light to the front and/or a side of thevehicle, the communication system 1500 increases the visibility of thevehicle increasing the probability that the vehicle will be seen byother turning and merging vehicles during travel.

Embodiments of the present invention provide the driver of a subjectvehicle a communication system that provides warning signals to othervehicles of any deceleration or possibility of braking of the subjectvehicle. One novel and distinguishing feature of this invention is thatthe subject vehicle's communication system warns other vehicles of anypossibility that the subject vehicle will begin to brake. This is sobecause any engagement of the brake pedal is usually immediatelypreceded by a disengagement of the throttle.

Thus, this invention provides an earlier warning to the driver of thefollowing vehicle of a subject vehicle's intent to decelerate than iscurrently available in modern vehicles, which only provide systems thatactuate warning lamps if the driver depresses the brake pedal or if anaccelerometer unit detects a threshold deceleration. Modern driversrespond quickly to rear brake warning lamps, conditioning that thepresent invention takes advantage of by using these warning systems toconvey new and broader warnings. Since following distances on modernroadways are often inadequate, this arrangement could prevent numerousrear-end collisions.

Example 2 Anti-Rollover Systems

In some embodiments of this invention, outputs from the sensing ofabsolute lateral acceleration are used to adjust suspension systems bystiffening outside suspension and/or loosening inside suspension ofmoving vehicles. Further, in some other embodiments, simple lateralacceleration is used to adjust suspension systems during turning.

When lateral acceleration or force is applied to a vehicle, it tends tolean in the direction opposite to the force being applied, due in partto the softness of their suspension systems. This moves the center ofgravity further off center and in some cases outside of their wheelbaseapproaching the critical rollover point. Stiffening the outsidesuspension and/or loosening the inside suspension keeps the center ofgravity of vehicles within a tighter envelope relative to the wheelbase.This inversely affects the propensity, especially in high center ofgravity loaded vehicles, to rollover when the center of gravity of theirload exceeds the wheelbase and reaches the critical rollover point.Additionally, by adjusting the suspension system in this manner thedistribution of load between left and right side wheels is kept moreeven resulting in improved traction.

The above can be accomplished either with an absolute lateralacceleration signal and a gyroscopic correction, or with an uncorrectedlateral acceleration signal. In the latter scenario, an accelerometermounted to sense lateral acceleration also detects a component ofgravitational acceleration during a banked turn. The strength of thegravitational component relative to the lateral (centrifugal)acceleration will depend on the speed of the turn. Correction to thesuspension system is performed accordingly. In addition, this type ofsuspension adjustment system could be used only when the vehicle isturning. A gyroscope mounted in the horizontal plane to sense heading(e.g. FIG. 2A) could be used to sense whether the vehicle is turning ornot.

Typically these are configured as pulse width modulated (PWM)controlling devices. Such devices typically accept analog voltage levelinputs, which are then converted to a corresponding pulse width output.Such outputs are a common method of controlling and delivering aregulated amount of current to a device such as a hydraulic solenoid.The hydraulic solenoids of course are responsible for increasing,decreasing or maintaining pressure levels within the hydraulic orpneumatic suspension system.

An anti-rollover device 400 using an absolute acceleration signal isillustrated in FIG. 4. In this embodiment vehicles are assumed to beequipped with adjustable suspension systems, typically hydraulic orpneumatic. When absolute lateral acceleration is sensed theaccelerometer-gyroscopic sensor 410 sends a signal representing absolutelateral acceleration to a suspension selector 420, which passes signalsalong to a controller responsible for controlling the relevant quadrantof the suspension. The suspension selector 420 must interpret the signalto determine the appropriate quadrant. For example, Q1, in whichsuspension system 432 is controlled by suspension control 431 could bethe right front wheel; Q2, in which suspension system 442 is controlledby suspension control 441 could be the left front wheel; Q3, in whichsuspension system 452 is controlled by suspension control 451 could bethe right rear wheel; and Q4, in which suspension system 462 iscontrolled by suspension control 461 could be the left rear wheel. Ofcourse, other orderings are possible, as are systems with only twoindependent zones, e.g. two sides are controlled in lockstep.

An anti-rollover device 800 using a lateral accelerometer is illustratedin FIG. 8. In this embodiment vehicles are assumed to be equipped withadjustable suspension systems, typically hydraulic or pneumatic. Whenlateral acceleration is sensed the accelerometer 810 sends a signalrepresenting lateral acceleration to a suspension selector 820, whichpasses signals along to a controller responsible for controlling therelevant quadrant of the suspension. The suspension selector 820 mustinterpret the signal to determine the appropriate quadrant. For example,Q1, in which suspension system 832 is controlled by suspension control831 could be the right front wheel; Q2, in which suspension system 842is controlled by suspension control 841 could be the left front wheel;Q3, in which suspension system 852 is controlled by suspension control851 could be the right rear wheel; and Q4, in which suspension system862 is controlled by suspension control 861 could be the left rearwheel. Of course, other orderings are possible, as are systems with onlytwo independent zones, e.g. two sides are controlled in lockstep.

Example 3 Performance Monitoring Systems

Due to fuel efficiency goals and competitive pressures late modelvehicles have the ability to monitor engine system performance throughan array of sensors and detectors. The absolute accelerometer/gyroscopecombination provides the ability to communicate actualpower-to-the-ground data for use in engine/vehicle performancecomputations. In this embodiment, the accelerometer-gyroscopic sensorcontinuously sums absolute acceleration values to provide both absoluteacceleration and actual speed values, which can be used by amanufacturers vehicle computer unit (VCU).

For example, the system 500 shown in FIG. 5 includes theaccelerometer-gyroscopic sensor 510, which delivers actual speed dataand absolute acceleration data to a vehicle computer unit (VCU) 520 (orat least the engine monitoring portion thereof). The VCU 520 usesbaseline engine performance data 540 to either self-correct through afeedback mechanism, or to issue a warning through the performancewarning system.

The manufacturer's baseline engine performance data is helpful indetermining how much acceleration should be achieved for a given amountof throttle and what the speed of the vehicle should be for a givenamount of throttle. For instance, a VCU may have tuned to maximumefficiency however the vehicle's corresponding speed or acceleration maybe many percentage points less than what would be expected, indicatingperhaps that the tire pressure is low or that the vehicle is loaded to ahigher level than what would be normal, in which case the tire pressureshould be increased.

Example 4 Road or Suspension Condition Monitoring Systems

Because an accelerometer-gyroscopic sensor, which is used and is part ofthis invention can use one axis of a dual axis accelerometer in thevertical position vertical acceleration output signals are madeavailable to other monitors or computers that require this information.Such a requirement may be to monitor and evaluate road quality and/orshock absorber utilization and performance. For instance, it is apparentto a rider in a vehicle when such vehicle is riding on worn out shockabsorbers. However, it becomes less apparent when those shock absorberswear out slowly over an extended period of time. The first time a drivermay realize that shock absorbers have worn out is in cases wherecritical performance is required. Or when they replace worn out tiresand see the evidence on tires of worn out shock absorbers. The absoluteA/G sensor detects vertical acceleration in very small increments.Increasing levels of vertical acceleration can easily be monitored thusproviding notice to drivers of the degradation of shock absorber system.

For example, in the system 600 shown in FIG. 6, theaccelerometer-gyroscopic sensor 610 provides absolute verticalacceleration data to a VCU 620 or at least a suspension-monitoringportion thereof. The VCU 620 can use baseline suspension performancedata 640 to either self-correct through a feedback mechanism or issue awarning through the suspension warning system 630.

Example 5 Navigation Systems

In most embodiments, the accelerometer-gyroscopic sensor is continuouslymonitoring acceleration; a unit of acceleration multiplied by a unit oftime yields a unit of velocity (with speed as its magnitude). In someembodiments, the accelerometer-gyroscopic sensor continuously sums unitsof acceleration over small increments of time. In this case, theaccelerometer-gyroscopic sensor provides the integrated velocity orspeed as an output. In some embodiments, when a horizontally mountedgyroscope is incorporated, the accelerometer-gyroscopic sensor alsoprovides direction or heading as an output.

Because velocity, or speed and heading are the raw elements required forinertial navigation systems. In the system 700 shown in FIG. 7, theaccelerometer-gyroscopic sensor 710 provides actual speed and headinginformation as an output to a navigation system controller 720. Thenavigation system controller 720, which normally provides navigationdata from a global positioning system (GPS) 730 directly to thenavigation system input/output (I/O) 750, incorporates headinginformation from the accelerometer-gyroscopic sensor 710 during periodsof connection loss with the GPS satellite system. In return forproviding the heading data to the inertial navigation system 740, thenavigation controller receives navigation data from the inertial systemto supplement or replace its GPS data.

In some embodiments, the navigation system controller 720 also providesGPS heading data back to the accelerometer-gyroscopic sensor 710 topermit re-referencing of the gyroscopes contained therein. Continuousreferencing and re-referencing of the horizontally mounted gyroscopeutilize GPS heading values while satellite signals are acquired. Oncesatellite signals are lost gyroscopic heading values take priority usinglast known valid headings from the GPS. This method using absolute A/Gvalues for supplementing data to the GPS data when the GPS system haslost signal will find use in many applications outside of the automotiveindustry.

These elements in output signal format are made available to on boardGPS based navigation systems through a data port for supplementationduring periods of lost or down satellite signals so that the user of aGPS navigation system sees no down time during these periods.

In another aspect, since speed or velocity can be tracked by summingpositive and negative accelerations and multiplying by time, a secondmultiplication by time can yield distance, which is also useful innavigation.

Example 6 Altimeter Systems

In another aspect, summing positive and negative vertical accelerationsover time yields altitude. For example, an instrument, including anaccelerometer-gyroscopic sensor, placed in an airplane or other flyingobject, contains a circuit that continuously sums over all accelerationsand outputs altitude. Alternatively, a system including anaccelerometer-gyroscopic sensor included in a non-flying vehicle trackschanges in altitude and outputs a signal used to vary engine performanceor some other type of parameter.

This method of altitude determination has certain advantages overcurrent methods of determining altitude which rely on either radar,pressure sensors, or GPS triangulation. Of course its accuracy indetermining altitude above sea level (ASL) relies on knowledge ofinitial altitude, and its accuracy in determining altitude above groundlevel (AGL) relies on terrain maps or something similar. Since this typeof instrument would reveal nothing about a changing ground level belowan aircraft, any aircraft equipped with it would still require a radaraltimeter for determining AGL on instrument approaches that requiresuch.

Example 7 Dynamic Suspension Adjustment Systems

In some embodiments of this invention, outputs from the sensing oflateral acceleration are used to adjust suspension systems by stiffeningoutside suspension and/or loosening inside suspension of movingvehicles.

When lateral acceleration or force is applied to a vehicle, it tends tolean in the direction opposite to the force being applied, due in partto the softness of their suspension systems. This moves the center ofgravity further off center and in some cases outside of their wheelbaseapproaching the critical rollover point. Stiffening the outsidesuspension and/or loosening the inside suspension keeps the center ofgravity of vehicles within a tighter envelope relative to the wheelbase.This inversely affects the propensity, especially in high center ofgravity loaded vehicles, to rollover when the center of gravity of theirload exceeds the wheelbase and reaches the critical rollover point.Additionally, by adjusting the suspension system in this manner thedistribution of load between left and right side wheels is kept moreeven resulting in improved traction.

Typically these are configured as pulse width modulated (PWM)controlling devices. Such devices typically accept analog voltage levelinputs, which are then converted to a corresponding pulse width output.Such outputs are a common method of controlling and delivering aregulated amount of current to a device such as a hydraulic solenoid.The hydraulic solenoids of course are responsible for increasing,decreasing or maintaining pressure levels within the hydraulic orpneumatic suspension system.

An anti-rollover device 400 is illustrated in FIG. 4. In this embodimentvehicles are assumed to be equipped with adjustable suspension systems,typically hydraulic or pneumatic. When absolute lateral acceleration issensed the accelerometer-gyroscopic sensor 410 sends a signalrepresenting absolute lateral acceleration to a suspension selector 420,which passes signals along to a controller responsible for controllingthe relevant quadrant of the suspension. The suspension selector 420must interpret the signal to determine the appropriate quadrant. Forexample, Q1, in which suspension system 432 is controlled by suspensioncontrol 431 could be the right front wheel; Q2, in which suspensionsystem 442 is controlled by suspension control 441 could be the leftfront wheel; Q3, in which suspension system 452 is controlled bysuspension control 451 could be the right rear wheel; and Q4, in whichsuspension system 462 is controlled by suspension control 461 could bethe left rear wheel. Of course, other orderings are possible, as aresystems with only two independent zones, e.g. two sides are controlledin lockstep.

In other embodiments, simple lateral acceleration is provided to asuspension control system.

Example 8 System for Turning Off an Idling Engine

In further embodiments, a vehicle speed sensor (VSS) 1010 such asdescribed above, is configured to sense a lack of motion of a vehicle.FIG. 10 is a schematic view illustrating the components of a vehiclemonitoring system 1000, warning other drivers of the stationary statusof a vehicle and turning off the engine after the vehicle has beenstationary for a period of time. The vehicle monitoring system 1000comprises a VSS 1010, an idling timer 1015, a transmission statusdetector 1020 and a control device 1040. In some embodiments, the idlingtimer 1015 is a distinct microprocessor coupled to the VSS 1010 and thecontrol device 1040. In some embodiments, the idling timer 1015 is amicroprocessor comprised within the control device 1040. The VSS 1010emits a periodic function with a frequency corresponding to a motionstatus of the vehicle and sends a signal to the idling timer 1015 or thecontrol device 1040. The transmission status detector 1020 is alsocoupled to the control device 1040 and detects whether the transmissionis in park or neutral and sends a signal to the control device 1040, asindicated above. In some embodiments, the system comprises an emergencybrake detector 1030, which is coupled to the control device 1040 andsends a signal to the control device 1040 corresponding to theengagement of the emergency brake. In some embodiments, the systemcomprises an external temperature sensor 1070, which is coupled to thecontrol device 1040 and sends a signal to the control devicecorresponding to the temperature of the external operating environment.In some embodiments, the control device 1040 only turns off the vehicleif the external temperature is above a programmed value. In someembodiments, the external temperature sensor 1070 only sends a signal ifthe external temperature is above a programmed value.

After receiving a signal that the vehicle is stationary, the controldevice 1040 activates an alerting device to signal to other drivers thatthe vehicle is stationary and the idling timer 1015 is also activated.In some embodiments, the alerting device is a rear facing amber light,which warns following vehicles of the stationary status of the subjectvehicle. In some embodiments, the idling timer 1015 is a microprocessorcomprised within the control device 1040 such that the control deviceactivates the timer. Once the timer reaches a pre-programmed period, theidling timer 1015 sends a signal to the control device 1040. The controldevice 1040 processes the input signal it receives from the idling timer1015 and the transmission status detector 1020 and decides whether toturn off the engine of the vehicle. In some embodiments, the controldevice 1040 only turns off the vehicle if the vehicle is stationary andthe transmission is in park. In some embodiments, the emergency brakeengagement detector 1030 additionally sends a signal to the controldevice 1040. In these embodiments, the control device 1040 only turnsoff the vehicle if the emergency brake is additionally engaged, althoughthe transmission may be in park or neutral. In further embodiments, theexternal temperature sensor 1070 sends a signal to the control device1040. In these embodiments, the control device 1040 only turns off thevehicle if the external temperature is above a programmed value. In someembodiments, the external temperature sensor 1070 only sends a signal ifthe external temperature is above a programmed value.

The idling timer 1015, is configured to send a de-activation signalafter the timer has reached the end of its pre-programmed period. Insome embodiments, the idling timer 1015 is configured to reach the endof its pre-programmed period after some predetermined period of time,such as 1, 3, 6 or 9 minutes. In other embodiments, the idling timer1015 is configured to reach its pre-programmed period of time after someother period of time.

After the idling timer 1015 has reached the end of its pre-programmedperiod of time, a variety of signals and types of signals are sent toturn off the engine. In some embodiments, a logic high or logic lowsignal is sent directly to the control device 1040, which turns off theengine. In other embodiments, a 12V signal is sent to a relay whichresides in series with the ignition system. Receiving the 12V signalactivates the relay and disengages the ignition. In further embodiments,additional signals are sent to relays or other such devices to turn offa lighting system or other accessory equipment.

In some embodiments, additional safety features such as redundantqueries confirming “park-status” are included. The safety featuresinclude querying emergency brake status, transmission engagement statusand foot-pedal brake status. In these embodiments, signals to turn offthe engine are delayed until such “park-status” is confirmed.

FIG. 11 illustrates the process used to turn off an idling vehicle. Theprocess of FIG. 11 starts at the step 1102. At the step 1104, the systemdetermines whether the vehicle is stationary based on output from theVSS. If the vehicle is stationary, then at the step 1106, an alertingdevice to warn following vehicles of the stationary status and an idlingtimer are activated. As discussed above, the idling timer 1015 isconfigured to run for a pre-programmed period of time. At the step 1108,the system determines whether the idling timer 1015 has run for itspre-programmed period. In some embodiments, the idling timer 1015 sendsa signal to the control device 1040 when it has run for itspre-programmed period. If the timer has reached the end of itspre-programmed period, then the system proceeds to the step 1110. At thestep 1110, the system queries the vehicle's transmission status based oninput from the transmission status detector 1020 to the control device1040 (FIG. 10). In some embodiments, the system queries whether thevehicle's transmission is in park. In some embodiments, the systemqueries whether the vehicle's transmission is in neutral or park. Whenthe system queries whether the vehicle's transmission is in neutral, thesystem also queries whether the emergency brake is engaged based oninput from the emergency brake engagement detector 1030 to the controldevice 1040 (FIG. 10). In further embodiments, the system separatelyqueries whether the emergency brake is engaged based on input from theemergency brake engagement detector 1030 to the control device 1040. Ifat the step 1110 the vehicle's transmission is in park, then the systemproceeds to the step 1112. At the step 1112, the system queries thetemperature of the external operating environment. If at the step 1112,the temperature is at or below the programmed temperature, then a signalis not sent to turn off the engine and the engine is allowed to idle.The engine is allowed to idle such that a taxi-driver or other vehicleoperator is able to allow the vehicle to run on a cold day while theyare waiting for a fare or in other comparable situations. If at the step1112, the temperature is above the programmed temperature, a signal issent to turn off the engine and the process ends at the step 1114. Insome embodiments, additional signals are sent at the step 1114 to relaysor other such devices to turn off a lighting system or other accessoryequipment.

In some embodiments, the process illustrated in FIG. 11 furthercomprises redundant queries confirming the “park-status” of the vehicle.These include querying the emergency brake status, querying thetransmission engagement status and querying the foot-pedal brake status.In these embodiments, a signal sent to turn off the engine is delayeduntil such “park-status” is confirmed.

Embodiments of the invention provide the driver of a subject vehicle asystem that causes an idling engine to turn off whose vehicle has beenstationary for more than a certain amount of time, whose transmission isin park or neutral with the emergency brake activated and where theoutside temperature is above a threshold value. The system is able toselectively turn off an engine according to the outside temperature anda pre-programmed time period of engine idle.

Thus, the invention is able to automatically turn off an idling engineafter a variety of different time periods and at a variety of differenttemperatures. This is advantageous over most modern vehicles which mustbe manually turned off and then restarted by the vehicle's operator. Anovel and unique way for corporate and governmental fleet operations aswell as individual operators to save money and prevent undueenvironmental pollution caused by engine idle is described herein.

Of course, the present invention has additional uses that are notdiscussed in the embodiments above. The present invention has beendescribed in terms of specific embodiments incorporating details tofacilitate the understanding of the principles of construction andoperation of the invention. As such, references herein to specificembodiments and details thereof are not intended to limit the scope ofthe claims appended hereto. It will be apparent that those skilled inthe art that modifications can be made to the embodiments chosen forillustration without departing from the spirit and scope of theinvention.

We claim:
 1. A communication system for a following vehicle, comprising:a. a receiver to receive a non-visual signal from a lead vehicleindicating a deceleration, but not a braking of the lead vehicle; b. aresponse device that generates an alert to warn of the change in thetraveling speed of the lead vehicle; and c. a control device coupled tothe receiver and the response device, wherein the receiver sends asignal to the control device corresponding to the deceleration of thelead vehicle and the control device operates the response device in amanner dependent on the deceleration of the lead vehicle and a travelingspeed of the following vehicle.
 2. The communication system of claim 1,wherein the signal comprises one or more of infrared, infrared laser,radio frequency, wireless, WiFi, and Bluetooth®.
 3. The communicationsystem of claim 1, wherein the signal corresponds to a decelerationstatus of the lead vehicle.
 4. The communication system of claim 1,wherein the signal comprises digital information.
 5. The communicationsystem of claim 1, wherein the signal is transmitted from an alertingdevice that modulates the signal at a specific frequency which isreceived by the receiver which only recognizes the signal at thespecific frequency.
 6. The communication system of claim 5, wherein thespecific frequency comprises 38 KHz.
 7. The communication system ofclaim 5, wherein the specific frequency comprises 100 Hz.
 8. Thecommunication system of claim 1, wherein the response device generates avisual alert.
 9. The communication system of claim 1, wherein theresponse device generates an auditory alert.
 10. The communicationsystem of claim 1, wherein the alert corresponds to the actual speed ofthe lead vehicle.
 11. The communication system of claim 1, furthercomprising a speed control system coupled to the control device, whereinthe control device operates the speed control system in a mannerdependent on the traveling speed of the lead vehicle.
 12. A system forcommunicating a change in a traveling speed of a vehicle, comprising: a.an alerting device placed in a first vehicle that transmits a non-visualsignal indicating a deceleration, but not a braking of the firstvehicle; b. a receiver placed in a second vehicle that receives thenon-visual signal sent by the alerting device; and c. a response devicethat generates an alert in a manner dependent on the deceleration thefirst vehicle and a traveling speed of the second vehicle.
 13. Thesystem for communicating the traveling speed of a vehicle of claim 12,wherein, wherein the non-visual signal comprises one or more ofinfrared, infrared laser, radio frequency, WiFi, and Bluetooth®.
 14. Thesystem for communicating the traveling speed of a vehicle of claim 12,wherein the signal corresponds to a deceleration status of the firstvehicle.
 15. The system for communicating the traveling speed of avehicle of claim 12, wherein the signal comprises digital information.16. The system for communicating the traveling speed of a vehicle ofclaim 12, wherein the alerting device modulates the signal at a specificfrequency which is received by the receiver which only recognizes thesignal at the specific frequency.
 17. The system for communicating thetraveling speed of a vehicle of claim 16, wherein the specific frequencycomprises 38 KHz.
 18. The system for communicating the traveling speedof a vehicle of claim 16, wherein the specific frequency comprises 100Hz.
 19. The system for communicating the traveling speed of a vehicle ofclaim 12, wherein the response device generates a visual alert.
 20. Thesystem for communicating the traveling speed of a vehicle of claim 12,wherein the response device generates an auditory alert.
 21. The systemfor communicating the traveling speed of a vehicle of claim 12, whereinthe alert corresponds to the actual speed of the first vehicle.
 22. Thesystem for communicating the traveling speed of a vehicle of claim 12,further comprising a control device placed in the second vehicle coupledto a speed control system and the receiver, wherein the receiver sends asignal to the control device corresponding to a change in the travelingspeed of the first vehicle and the control device operates the speedcontrol system in a manner dependent on the traveling speed of the firstvehicle.
 23. The system for communicating the traveling speed of avehicle of claim 12, wherein the alerting device and the receiver areinstalled as aftermarket equipment.
 24. A method of alerting drivers toa change in the traveling speed of a vehicle, comprising: a. determiningan absolute deceleration of a first vehicle; b. determining a brakingstatus of the first vehicle; b. if the first vehicle is decelerating,but not braking, transmitting a non-visual signal from the firstvehicle; c. receiving the non-visual signal at a second vehicle; and d.generating an alert at the second vehicle in a manner dependent on thedeceleration of the first vehicle and a traveling speed of the secondvehicle.
 25. The method of claim 24, wherein the non-visual signal andthe alert correspond to the actual speed of the first vehicle.
 26. Themethod of claim 24, wherein the non-visual signal is an infrared signalmodulated at a specific frequency which is received by a receiver placedin the second vehicle which recognizes the signal only at the specificfrequency.
 27. The method of claim 26, wherein the specific frequencycomprises 38 KHz.
 28. The method of claim 26, wherein the specificfrequency comprises 100 Hz.
 29. The method of claim 24, wherein thealert is visual.
 30. The method of claim 24, wherein the alert isauditory.
 31. The method of claim 24, wherein the second vehicle furthercomprises a control device coupled to a speed control system and thereceiver, wherein the receiver sends a signal to the control devicecorresponding to the traveling speed of the first vehicle and thecontrol device operates the speed control system in a manner dependenton the traveling speed of the first vehicle.
 32. The communicationsystem of claim 1, wherein the response device generates an alertannouncing that the vehicle is traveling too close to the lead vehicle.33. The communication system of claim 32, wherein the response devicegenerates an alert that the following vehicle is traveling at an unsafedistance from the vehicle based on its current speed.
 34. Thecommunication system of claim 33, wherein the unsafe distance increaseswith an increase in speed of the vehicle.
 35. The communication systemof claim 32, wherein the response device generates an alert announcing“YOU HAVE ENCROACHED ON THE SAFE SEPARATION ZONE.”